Endless track assembly



Sept. 12, 1961 R. T. BAUGH ENDLESS TRACK ASSEMBLY 2 Sheets-Sheet 1Original Filed Aug. 15, 1956 JQMO Sept. 12, 1961 R. T. BAUGH ENDLESSTRACK ASSEMBLY 2 Sheets-Sheet 2 Original Filed Aug. 15, 1956 ML /gymime/y United States Patent F I 2,999,581 ENDLESS TRACK ASSEMBLY RobertT. Baugh, Brookfield, Wis., assignor to Allis- Chalmers ManufacturingCompany, Milwaukee, Wis. Original application Aug. 15, 1956, Ser. No.604,223, now Patent No. 2,959,364, dated Nov. 8, 19'60. Divided and thisapplication Mar. 10, 1958, Ser. No. 720,252 2 Claims. (Cl. 198- 165)This invention relates generally to improvements in the art pertainingto endless tracks and more particularly to an improved movable endlessload bearing track assembly including means for supporting such tracksso that they can be subjected to intense bearing forces without anyimpairment of mobility.

This application has been divided from my copending application withRichard F. Anderson and Dimitri B. Kececioglu, Serial No. 604,223, filedAugust 15, 1956, titled Comminution Apparatus, now United States LettersPatent No. 2,959,364.

Essential the present invention provides a unique combination ofelements and members into means for supporting and maintaining operativerolling tracks of the endless belt type when these tracks are subjectedto intense bearing forces. Such forces are imposed upon the track in anumber of applications such as when they are in combination withcomminution apparatus of the type described in my aforesaid copendingapplication, when they are used as high capacity load conveyers, or whenthey are in combination with tank housings, crane housings and othercrawler driven vehicles and the like.

Devices have heretofore been proposed'in an attempt to provide adequatesupport for and insure the mobility of load bearing endless tracks butnone has obtained the total succes desired. For example, one of theproposed devices comprised an endless track and a thick rectangularplate disposed immediately behind the bearing surface of the track. Inoperation, however, the forces directed against the track drove itfirmly against the plate and created a friction resistance which greatlyimpaired the mobility of and, indeed, substantially halted the movementof the track.

Another proposed device comprised an endless track reeved over aplurality of spaced cylinders extending transversely of the path oftrack movement. The cylinders were pivotally mounted to a housing memberand rotated with the frame. reducing the friction resistance, which wasa problem of former devices, this device, by the very manner in which itovercame the friction, created a new and an even more serious problem.Overloading and breaking of parts were common with this device because,except for those portions of the track passing against the variouscylinders, the track chains were forced to endure most of the load intension with the result that they were frequently broken.

According to the present invention an endless track assembly is providedwhich eliminates the high friction 'resistance and Chain overloadingwhich rendered theprior art assemblies disadvantageous and undesirable.The

While somewhat successful in endless track assembly of thepresent'invention includes support means in which forces placed upon anendless is disposed in an idler raceway defined by and'disposed PatentedSept. 12, 1961 intermediate of the supporting shoe and the endlessbearing track. The endless idler roller belt resides in intimateantifn'ction engagement with the supporting shoe and the endless trackand is characterized by its ability to maintain the mobility of thetrack relative to the shoe while simultaneously dissipating the bearingforces applied to the track and comprises in its preferred form aplurality of individually mounted chain linked pivotable rollers forfree and independent engaging substantially frictionless movement withopposing surfaces of the track and shoe.

Accordingly it is a prime object of the present invention to provide asupport means for a moving endless track which enables frictionresistance between the track and the means to be reduced to anoperationally insignificant value while simultaneously enabling thetrack to endure greater loads and forces than heretofore possiblewithout overloading or mechanical failure.

Another object of the present invention is to provide support means formoving endless tracks in which the cooperative coaction of its severalelements and members permits the use of such tracks under forceconditions which heretofore they were unable to endure.

A still further object of the present invention is to provide supportmeans for moving endless load bearing tracks in which forces aredissipated by and transmitted from the bearing surface of a track to asupporting shoe by an endless freely moving idler roller belt interposedbetween the track and the shoe in an idler raceway defined therebetween.

These and other objects as will appear are fulfilled by the presentinvention in a manner which can be readily discerned from the followingdetailed description when read in conjunction with the accompanyingdrawing.

In the drawing:

FIG. 1 is an isometric view of a typical combination embodying thesupport means of the present invention; a FIG. 2 is a side elevationpartially in cross section of the apparatus in FIG. 1 showing in greaterdetail the support means of the present invention;

FIG. 3 is a partial view in section taken along line III-III of FIG. 2;

FIG. 4 is an enlarged view partially in section, with parts broken awayfor clarity, showing an endless load bearing track and an idler rollerchain reeved over a shaft mounted sprocket wheel in accordance with oneembodiment of the present invention; and

FIG. 5 is a plan view with parts broken away for clarity showing therelationship of the track bearing plate and the idler belt of FIG. 4.

In the accompanying drawing (see FIG. 1) comminution apparatus, such asthat described in my copending application, has been chosen toillustrate an operative combination embodying the present invention.

The comminution apparatus, indicated generally at 10, comprisesessentially a housing 11 and a base 12. Housing 11 is preferably formedin two sections, such as end portions 13, 14, which are retractablerelative to each other for reasons not germane to this instantdiscussion. Each of the end portions 13, 14 contain an assemblyembodying the present invention and therefore, for the purpose ofdescribing my preferred embodiment, reference to either of the endportions may be considered equally applicable to both. Further, toenhance the clarity of the drawing, certain of the details have beenshown relative to the assembly in end portion 13 while others have beenshown relative to end portion 14. To maintain the relationship of thevarious parts with a minimum of confusion, the corresponding parts ofthe two assemblies will each bear the same reference numeral, the onlyfactor to be remembered is that the assembly in end portion 13 is themirror image of the assembly in end portion 14.

An assembly according to the present invention comprises (relative tothe drawing) an upper shaft 15 and a lower shaft 16, each extendingtransversely of the sides of the end portion in substantially parallelspaced relationship to each other and each being rotatably mountedrelative thereto in suitable bearings 17. At least one of the shafts,e.g., shaft 16, is mechanically coupled to a suitable motor assembly 18and is driven in response thereto.

Each shaft, for example shaft 16 as shown in FIG. 3, has a pair ofsprocket wheels 21, 22 mounted thereon in integral relationship thereto.One sprocket wheel 21 is mounted adjacent one end of shaft 16 while theother, wheel 22, is mounted adjacent the other end of shaft 16. Similarsprocket wheels 23 and 24 are similarly mounted adjacent the respectiveends of shaft 15. The several sprocket wheels are secured to theirrespective shafts in any suitable manner such as with keys 25 (see FIG.4).

A chain 26 is reeved vertically (relative to the drawing) about sprocketwheels 21 and 23 which, as described, are positioned adjacent a commonside of the end portion while another chain 27 is reeved verticallyabout sprocket wheels 22 and 24, the corresponding wheel on shaft 15.Again, both of these wheels, as described, are similarly positionedadjacent the other common side of the end portion. Thus as chains 26 and27 circumscribe and coact with their respective sprocket wheels, adirect mechanical linkage is provided between shaft 15 and shaft 16.

The relative distance between shafts 15, 16 and hence, the tension inchains 26, 27 is adjustable with suitable take up bearings 28 (shown inFIG. 1) operatively associated with and including journal bearings 17 ofshaft 16.

In the illustrative embodiment (see FIG. 2), an endless load bearingtrack 30 is mounted in end portion 14 and comprises a plurality oftreads 31 which may be mounted upon chains 26, 27 in any suitable mannersuch as by sliding tread flange 32 into chain link 33 as in FIG. 4.

Mounted operatively adjacent endless load bearing track 30 (or track asit shall be called) is an endless idler belt 35 which circumscribesshafts 15, 16 and is bounded laterally by chains 26, 27. Idler belt 35comprises a plurality of rotatably mounted rollers 36 connected at theirends by linking means 37 which flexibly secure each roller insubstantially parallel spaced relationship to each adjacent roller as isparticularly shown in FIG. 4. Thus treads 31, when mounted in chains 26,27 to define track 30, circumscribe the idler belt 35 and ridethereupon. Idler belt 35 provides antifriction means whereby treads 31may ride easily across an adjustable supporting assembly 40 which willhereafter be more fully described.

Idler belt 35 provides antifriction means by its particularcharacteristic of being intermittently movable with track 30 while eachindividual roller 36 continuously rotates upon its rotatable mounting,i.e., linking means 37.

It thus becomes apparent that the antifrictional characteristic of therotatably mounted rollers greatly reduces the friction which wouldotherwise exist if track 30 were operatively dragged directly againstthe substantially rigid surface of the adjustable supporting assembly 40disposed adjacent thereto. Linking means 37, which are disposed on eachend of roller 36, define the side boundaries of idler belt 35 and arerestrained laterally by chains 26, 27.

Idler belt 35 further enables the forces placed upon the bearing surfaceof the endless track 30 to be readily transferred from the treads 31 tothe adjustable supporting assembly 40 and hence to the housing 11. Theload is more uniformly distributed and therefore more easily transferredbecause of the uniform ladderlike arrangement which idler belt 35presents track 30 for receiving the loads placed upon the track. Theextended area provided by idler belt 35 diminishes unit loads by furtherdistributing random point loads in more or less snowshoe fashion.

As previously mentioned, the assembly of the present invention furthercomprises an adjustable supporting assembly 40 operatively disposedbetween opposed runs of idler belt 35 intermediate the sides of the endportion, e.g., end portion 14. Assembly 40 comprises a support ing shoe42 and a shoe mounting plate 44. Supporting shoe 42 is positionedadjacent that portion of idler belt 35 which is adjacent the bearingsurface of track 30 in such a manner that idler belt 35 is literallysandwiched between track 30 and supporting shoe 42. Thus the forcescreated upon the bearing surface of track 30 and transferred to idlerbelt 35 are further transferred to supporting shoe 42.

Supporting shoe 42 may be rigidly secured to shoe mounting plate 44 byany suitable means such as by bolts or rivets (not shown). Supportingshoe 42, when in assembled position is thus interposed between idlerbelt 35 and shoe mounting plate 44, and the complete assembly isdisposed generally transversely of the sides of the end portion.

The unique coaction between the bearing surface of the endlms track 30and supporting shoe 42 gives rise to further advantages the extent ofwhich have not been completely explored even at this date. Duringoperation the general contour of the load bearing surface of track 30will be that of supporting shoe 42 since the forces imposed upon thetrack 30 force the track 30 and idler belt 35 into intimate conformitywith the face contour of supporting shoe 42. Thus depending upon theapplication in which the assembly of the present invention is to beused, the contour of the supporting shoe 42 may be changed so that themost efiicient contour for the job can be readily utilized in thepresent inventionmerely by the selection of a supporting shoe having thedesired contour. For most applications, it is believed that a shoehaving a slightly arcuate convex face contour defined by a constantradius of curvature will provide quite satisfactory results.

In one embodiment of the present invention, mounting plate 44 isadjustably mounted to housing 11 by suitable fasteners 46 which extendthrough suitable openings 48 defined in the housing sides into lockingengagement in suitable fastener receiving means 50 provided in each endof and defined by mounting plate 44 generally normal to the planesdescribed by the sides of the end portion. Thus mounting plate 44 may berigidly and detachably secured to housing 11.

Openings 48 may be defined in the housing sides so that they aresubstantially arcuate as shown in the drawing to provide adjustabilityto mounting plate 44 and shoe 42 with respect to the peculiarcharacteristics of the combination in which it is assembled. Whereadjustability is not an operating factor, these openings, as well asother openings which have been or will be herein defined for adjustmentpurposes, can be defined in terms of a single position and circularopenings will be satisfactory.

Mounting plate 44 further comprises a depending portion 52 having anorifice 54 defined therethrough for receiving and circumscribing aportion of shaft 16. Depending portion 52 assists in reinforcingsupporting shoe 42 and hence track 30 by providing a greater massadjacent shaft 16 which aids in the transmission of forces imposed inthat area. Depending portion 52 further cooperates with track 30 byguiding idler belt 35 as it passes from one of its runs to the other. Inapplications not requiring special reinforcement adjacent one end of thebearing surface of track 30, it is permissible to remove considerablemass from depending portion 52.

Supporting assembly 40 further comprises an idler belt guide plate 55(this member is shown in FIG. 2 with respect to end portion 14) whichmaintains the idler belt 35 in spaced relationship to the driven oridler shaft 15 and routes the upper transverse portion of the idler belt35 in its change of linear direction during rotation. As particularlyshown in H6. 2, guide plate 55 is arcuate and is disposed more or lessconcentrically of and partially circumscribes shaft 15. One end of guideplate 55 is secured to the uppermost end of the supporting shoe 42 byany suitable means such as by weldments 56.

Mechanical movement of the endless load bearing track 30 is provided byactuating the power source 18 and transferring its movement to shaft 16through the mechanical coupling described before.

A typical power source 18 may comprise a motor 60 having a sheave 61mounted on its power shaft 62 and coupled by a V-belt 63 to a secondsheave 64 mounted upon shaft 16. The radii of the sheaves 61, 64 may bevaried to attain a desired mechanical ratio therebetween or, if desired,motor 60 may be connected directly to shaft 16 and the coupling assemblyeliminated.

In operation of the present invention, the firmness of the bearingsurface presented by track 30 is controlled by the tension of chains 26,27, and more basically, by the relative displacement between the axis ofrotation of shafts 15, 16. Thus the tension in track 30 and morespecifically that in the chains 26, 27 can be set to any desired amountby manipulating the corresponding take up bearings 28 in the well knownmanner.

When such adjustments as may be desired have been made, the endlesstrack assembly of the present invention is ready to operate and highload forces may now be applied to the load bearing surface of the track.The resulting forces, as explained, are then transmitted through thetreads 31, to and through idler rollers 36 and hence to and throughsupporting shoe 42 and mounting plate 44 to housing 11.

Having thus described the structure of an apparatus embodying thepresent invention and its operation, it is understood that the apparatusis so described only to exemplify the invention and not to limit it.Such modifications as may readily occur to one skilled in the art areintended to be included with the spirit of this invention, the presentinvention being limited only by the scope of the appended claims.

What is claimed is:

1. In a combination comprising: a frame; a pair of vertically spacedsubstantially parallel rotatable shafts mounted in said frame forrotation relative thereto; sprocket wheels journaled upon each of saidshafts at the outer extremities thereof adjacent and within said frameto provide a first and second pair of wheels respectively adjacent eachside of said frame; a pair of endless chains mounted for movement withone another, one of said chains being reeved about said first pair ofwheels and the other of said chains being reeved about said second pairof wheels; a plurality of tread plates connecting corresponding portionsof said chains and cooperating therewith to define a substantiallycontinuous bearing surface for movement with said chains; a convexlycontoured support means mounted to said frame intermediate said shaftsfor holding said bearing surface to a convex contour during loadingthereof and for receiving the forces of loading from said bearingsurface and solely and directly transferring said forces to said framewithout loading said shafts; and antifriction load transmission meansinterposed between said bearing and said support means in circumscribingrelationship to said support means, said support means comprising: amounting plate having a body portion secured to said frame intermediateopposed runs of said bearing surface and a depending portion, saiddepending portion having an elongated bore defined therethrough anddisposed in spaced circumscribing relationship about the lowermost ofsaid shafts, said body portion having a force receiving surface infacing relationship to the Working portion of said bearing surface, asupport shoe mounted to said force receiving surface intermediate saidsurface and said antifriction load transmission means and extendingupwardly beyond said surface to an end, and arcuate guide means securedto said end and extending upwardly therefrom into spaced shieldingrelationship about the uppermost of said shafts.

2. An assembly for supporting a movable endless track for receivingintense loading without impairing the movability thereof, comprising: aframe; a pair of vertically spaced substantially parallel shafts mountedin said frame for rotation relative thereto; track carriers journaledupon each of said shafts adjacent and within said frame; a movableendless track being reeved about said shafts upon said track carriersand movable therewith relative to said frame; support means mounted tosaid frame intermediate opposed runs of said movable endless track andreceiving forces from said track during the loading thereof andtransferring said forces to said frame, said support means including amounting plate having a body portion secured to said frame and a bulbousdepending portion, said depending portion having an elongated boredefined therethrough circumscribing a major portion of the lowermost ofsaid shafts in spaced relationship thereto and a shoulder portion, saidbody portion having a force receiving surface in facing relationship tothe working portion of said endless track, a support shoe mounted tosaid force receiving surface of said body portion and seated upon saidshoulder portion intermediate said surface and said endless track andextending upwardly beyond said surface to an end having seating meansdefined thereupon, and arcuate guide means carried by said end in saidseating means and extending upwardly therefrom into spaced shielding,semicircumscribing relationship about. the uppermost of said shafts; andantifriction load transmission means interposed between said endlesstrack, and the adjacent surface of said supporting shoe, said guidemeans and the outer surface of said depending portion of said mountingplate, for reducing friction therebetween to maintain movable saidendless track while intense loading is applied thereto whereby saidforces of loading from said track are transmitted solely and directlythrough said supporting shoe and said mounting plate to said frame.

References Cited in the file of this patent UNITED STATES PATENTS966,493 Volk Aug. 9, 1910 1,659,733 Harbeck Feb. 21, 1928 1,699,764Solem Jan. 22, 1929 2,150,984 Near et al Mar, 21, 1939 2,186,776 Webb etal. Jan. 9, 1940 2,761,633 Sindzinski Sept. 4, 1956

